Collet-chamber retarding system for weapons

ABSTRACT

A weapon whose barrel terminates in cartridge-receiving chamber which, in the firing state, is surrounded by the sleeve of a breech-closing mechanism. The chamber is longitudinally slotted to define a set of flexible fingers extending rearwardly from an unslotted forward section. When the cartridge is fired, the resultant high gas pressure therein causes momentary dilation of the casing, which then presses outwardly against the forward section of the chamber and the set of fingers in the rear section threof. The pressure exerted by the casing against the forward section of the chamber produces a gas seal preventing the escape of gas into the breech of the weapon, while the pressure exerted against the set of fingers causes deflection thereof, whereby the fingers or clips associated therewith frictionally engage the inner surface of the surrounding sleeve to lock the breechclosing mechanism and to retard the release thereof until the gas pressure has diminished to a safe level, permitting the casing to contract to assume its original state.

[451 Feb. 26, 1974 United States Patent [191 Angell et a1.

[ COLLET-CHAMBER RETARDING SYSTEM [57] ABSTRACT A weapon whose barrel terminates in a cartridge- FOR WEAPONS receiving chamber which, in the firing stateTisibrrounded by the sleeve of a breech-closing mechanism. The chamber is longitudinally slotted to define a set of n mw w N S Mm n? "H.011 ms nmm 79 m n k mwdm o fi RNFY a r o t n e v .m N U flexible fingers extending rearwardly from an unslot- [22] Filed: Jan. 22, 1973 [21] Appl. No.: 325,306

ted forward section. When the cartridge is fired, the

resultant high gas pressure therein causes momentary dilation of the casing, which then presses outwardly against the forward section of the chamber and the set of fingers in the rear section threof. The pressure exerted by the casing against the forward section of the chamber produces a gas seal preventing the escape of gas into the breech of the weapon, while the pressure exerted against the set of fingers causes deflection thereof, whereby the fingers or clips associated there- [56] References Cited UNITED STATES PATENTS 89/180 with frictionally engage the inner surface of the sur- 42/76 R rounding sleeve to lock the breech-closing mechanism 89/26 and to retard the release thereof until the gas pressure 39/180 has diminished to a safe level, permitting the casing to contract to assume its original state.

2,297,693 10/1942 3,235,996 2/1966 Mai11ard.........

3,596,555 8/1971 Somers et a1. 3,611,873 10/1971 Ellison 9 Claims, 11 Drawing Figures Primary ExaminerSamue1 W. Engle Assistant ExaminerC. T. Jordan PATENTEDFEBZSISH SHEET 1 (If 3 COLLET-CHAMBER RETARDING SYSTEM FOR WEAPONS BACKGROUND OF THE INVENTION This invention generally relates to automatic and self-loading firearms wherein a union is momentarily formed between the barrel of the weapon and its breech block when the weapon is fired, and more particularly to a barrel chamber having a collet-like structure adapted to retard the separation of the barrel and breech block in order to maintain the union thereof until the discharge gas pressure has dropped to an acceptably safe level.

In weapons such as auto-loading rifles and submachine guns, a cartridge introduced through the breech is rammed into the cavity of a chamber formed at the end of the barrel the standard cartridge includes a tapered casing of thin metal, from whose mouth a projectile extends. The casing contains a propellant or powder which, upon ignition, produces an explosive force that ejects the projectile through the barrel. Such ignition is usually effected by a firing mechanism adapted to strike the head or primer end of the casing.

The casing of a cartridge serves to combine the projectile and the propellant therefor into a unitary, selfcontained assembly capable of being inserted and fired in the weapon for which it is designed. In addition, the casing carries out the vital function of creating a gas seal in the barrel chamber shortly after the propellant is ignited. This gas seal prevents gas at high pressure, whose primary function is to provide an ejecting force for the projectile, from blowing back into the breech of the gun and possibly causing injury to firing personnel, particularly if the high-pressure gas propels metallic fragments extracted from the casing.

To effect a gas seal, the casing must be fully surrounded by the complementary wall of the chamber for at least a short section extending rearwardly from the mouth of the casing. When the propellant is ignited, the resultant combustion gases which expand at a controlled rate exert pressure on the interior surfaces of the thin-walled casing, causing momentary expansion thereof. This dilation of the casing causes it to close the small gap between the casing and the surrounding chamber wall, thereby affording a tight gas seal.

After the propellant has been consumed and the residual gas pressure has dropped to a safe level, the natural elasticity of the casing causes the casing to return to its original size, thereby breaking the gas seal and permitting extraction of the casing from the weapon chamber preparatory to the introduction of the next round. The dilation of the casing must be within the elastic limits of the casing material, otherwise the casing will burst.

It is important, during this sequence of events initiated by firing, that the head or primer end of the casing be rigidly backed up, otherwise the high gas pressure may act to sever the heavier head from the thin-walled body of the casing, thereby jamming the weapon and releasing hot gases therein.

Various means have heretofore been proposed to utilize the gas pressure developed within the barrel immediately after firing to lock the breech mechanism in its closed state until the gas pressure has diminished sufficiently to allow the gun to be safely unbreeched.

Thus in US. Pat. No. 1,550,759, a lever is provided, one end of which, in one lever position, cooperates with the breech-locking mechanism to maintain the latter in its locking state. The opposite end of this lever is subjected to gas pressure within the barrel immediately upon the firing of the gun, whereby the lever acts to maintain the locking mechanism in its operative state until the gas pressure has diminished sufficiently to permit the safe opening of the breech.

In U.S. Pat. No. 2,297,693, a less complicated approach is taken, for in this instance the barrel chamber is provided with a thin wall section surrounded by a relatively thick collar associated with the breech-closing mechanism so that at the instant of explosion, the chamber will expand against the enclosing collar and hold it in position against axial or rotary movement, thereby preventing opening of the breech mechanism until the gas pressure has dropped to a safe level.

The present invention constitutes a significant improvement over the approach taken in US. Pat. No. 2,297,693, in that while the barrel chamber is expansible, its ability to do so is effected without sacrificing the basic structural strength of the chamber and without otherwise impairing the normal functional characteristics of the chamber.

SUMMARY OF THE INVENTION In view of the foregoing, it is the main object of this invention to provide an improved cartridge-receiving barrel chamber for automatic and self-loading weapons, which chamber is responsive to the momentary dilation of the cartridge casing resulting from high pressures encountered on discharge, to effect a tight gas seal and also to lock the breech-closing mechanism of the weapon and to retard the release of this mechanism until the gas pressure has dropped to an acceptably safe level.

More particularly, it is an object of this invention to provide a chamber of the above-type which is thickwalled and of high structural strength, the chamber having longitudinal slots therein in a rear section to define a set of flexible fingers extending from a front unslotted section, which front section in conjunction with the dilated casing carries out a gas sealing function, which rear section in conjunction with the dilated casing effects a breech locking action.

The structure of a slotted chamber section in accordance with the invention is comparable to that of a machine collet or expanding mandrel in that the yieldable fingers thereof deflect outwardly when subjected to an outwardly directed pressure, and return to their initial position when pressure is released.

A significant feature of the invention resides in the fact that the chamber fingers are provided with one or more ridges which act, in one embodiment of the invention, as frictional retarding surfaces with respect to a surrounding bolt sleeve, and in another embodiment thereof, as retainers for clips which act as frictional retarding surfaces.

Also an object of the invention is to provide an efficient weapon in which the union between the barrel and the breech-locking mechanism is maintained for an adequate period to prevent premature release of the breech-locking mechanism.

Briefly stated, these objects are attained in a weapon whose barrel is rigidly or movably supported within a receiver, the barrel terminating in a cartridge-receiving chamber disposed in the breech of the weapon. In the firing state, the chamber is surrounded by a sleeve associated with a breech-closing mechanism.

The rear section of the chamber is longitudinally slotted to define a set of flexible fingers which extend from an unslotted front section. When the cartridge is fired, the resultant high gas pressure therein causes momentary dilation of the cartridge casing, which then presses against the front rear sections of the chamber.

The pressure exerted by the casing against the unslotted front section of the chamber effects a gas seal therewith preventing the escape of gas into the breech. The pressure exerted against the set of fingers in the rear section of the chamber causes outward deflection thereof, whereby the fingers or clips associated therewith frictionally engage the surrounding sleeve to lock the breech-closing mechanism and to retard the release thereof until the gas pressure has diminished to a safe level and the casing has assumed its initial size.

OUTLINE OF THE DRAWINGS For a better understanding of the invention as well as other objects and further features thereof, reference is made to the following detailed description to be read in conjunction with the accompanying drawings, wherein:

FIG. 1 is a longitudinal section (left-hand) taken through a perspective view of a first preferred embodiment of a weapon which includes a collet-like chamber in accordance with the invention, the cartridge to be fired being shown before it enters the breech;

FIG. 2 is the same section, showing the cartridge within the breech ready to be rammed into the chamber;

FIG. 3 shows the cartridge in its ignition state, with the discharged projectile travelling down the barrel;

FIG. 4 is a separate perspective view of the chamber;

FIG. 5 is a transverse section taken through the chamber before the cartridge therein has been fired;

F IG. 6 is a transverse section taken through the chamber, just after the cartridge has been ignited;

FIG. 7 is a longitudinal section (left-hand) of a second preferred embodiment of a weapon which includes a collet-like chamber in accordance with the invention, the cartridge being shown in the chamber in its ignition state;

FIG. 8 is a longitudinal section taken through the chamber;

FIG. 9 is a transverse section taken through the chamber before the cartridge has been fired;

FIG. 10 is a transverse section taken through the chamber after the cartridge therein has been fired; and

FIG. 11 is an exploded view of the chamber.

DESCRIPTION OF THE INVENTION FIRST EMBODIMENT Referring now to the drawings, FIGS. 1 to 6 show a first preferred embodiment of the invention, in which embodiment the barrel of the weapon is movably held within a receiver, the barrel being driven forward under spring tension. In these Figures, the collet-like chamber in accordance with the invention is generally designated by numeral 10.

Chamber 10 is disposed in the forward end of the breech 11, and is integral with a barrel 12 which extends axially from the front end of the receiver 13. The barrel is held to the receiver by a barrel-retaining nut 14 which encloses a barrel-return spring 15 that is coiled about the barrel. An annular flange 12A formed on the barrel engages the rear end of spring 15 so that forward movement of the barrel results in compression of the spring.

The bolt group, which in FIG. 1 is shown in its full recoil state, is constituted by a bolt 16 whose head 17 is provided with a standard casing extractor 18. A bolt sleeve 19 surrounds bolt 16 and head 17. Interposed between the rear end of sleeve 19 and the buffer backplate and bolt stop 21 is a recoil spring 20. Also provided is a bolt-retaining and limit pin 22. The remaining components of the weapon are omitted from the drawing, since their functions are conventional and they form no part of the present invention.

Shown entering breech 11 from a suitable magazine or other source is a standard cartridge, generally designated by numeral 23. This cartridge includes a thinwalled, tapered metallic casing 23A from whose mouth extends a projectile 238, the casing being filled with a propellant and being provided with a primer head 23C. The configuration of the cavity of chamber 10 is such as to complement that of cartridge 23, so that when the cartridge is rammed into the chamber cavity, the casing 23A conforms thereto, and the projectile 23B protrudes into the barrel in readiness for discharge.

Referring now to FIG. 2, cartridge 23 is shown held to bolt head 17 by extractor 18, the cartridge being disposed within breech 11 in axial alignment with chamber 10. When the bolt is released, recoil spring 20 quickly drives bolt 16 and bolt sleeve 19 forward to ram cartridge 23 into the cavity of chamber 10 at the end of barrel 12. This ramming force is transmitted to the barrel, which is pushed forward in receiver 13 against the tension of barrel-return spring 15.

Before considering FIG. 3, which shows the gun after ignition, with the projectile 23B discharged from the cartridge casing and travelling down barrel 12, we must first understand the structure of chamber 10, for it is the nature of this structure which governs the operation of the gun in this state.

Chamber 10, shown separately in FIG. 4, is a heavywalled, cylindrical body of high structural strength. Cut into the rear section of this body are four longitudinally extending slots 8,, S S and S.,, which are spaced ninety degrees apart. The slots extend from the rear of the chamber to a point which falls short of the front, whereby the front section 10A of the chamber is unslotted, as in a conventional chamber, to define a cylindrical collar that in conjunction with the casing in its expanded condition, establishes an effective gas seal.

The slotted rear section of chamber 10 is collet-like, and is formed by a set of resilient fingers which, when the casing is dilated, deflect outwardly. Relief cuts are made on the exterior of chamber 10 in the slotted rear section thereof to create a first segmented annular ring 10B at the end of the chamber, and a second segmented annular ring 10C midway in the rear section. The segments of these rings form ridges on their associated fingers. These segmented rings, as will be later explained, act as frictional retarding surfaces or as a retainer for special clips serving both as frictional retarding surfaces and as slot sealing devices.

It is to be understood that the invention is not limited to a four-slot arrangement, and that a lesser or greater number of slots may be provided to define a collet having deflectable fingers.

Returning now to FIG. 3, it will be seen that in the ignition state, casing 23A is fully inserted in chamber 10, the head 17 of the bolt 16 abutting head 23C of the easing. The bolt sleeve 19, which has been urged forward by recoil spring 20, now completely surrounds the slotted rear section of chamber and blocks the breech 1 1. As a result of the action of the bolt group, barrel 12 is shoved forward to compress barrel-return spring 15 to an extent limited by barrel-retaining nut 14.

At this stage of cartridge combustion, the casing 23A has been caused to expand rapidly under high gas pressure. The dilated casing engages the front, collar-like section 10A of the chamber to effect a gas seal therewith. The dilated casing also presses against the rear collet-like section of the chamber to outwardly deflect the fingers and the segmented rings 10B and 10C thereof to engage and seize under high pressure, the interior wall of bolt sleeve 19.

This powerful frictional engagement between the ridged fingers of the collet section of the chamber and the bolt sleeve, locks the breech-blocking mechanism and acts to maintain a temporary union with the barrel. The bolt is prevented from retracting until the gas pressure has dropped to a safe level, at which point the casing contracts to its original size and the fingers, in returning to their initial position, disengage the bolt sleeve.

Because the barrel 12 is free to move a short distance within the limits defined by barrel flange 12A and retaining nut 14, it is permitted to shift backward while it is locked to bolt sleeve 19 and bolt 16. This backward movement achieves a greater retarding effect when compared to a fixed barrel, for when the travel of the barrel is arrested after a short distance, this assists the extractor 18 in dislodging the casing 23A from chamber 10.

FIG. 5 is a rear-view section taken through the breech, showing casing 23A inserted within the chamber and embraced by collet fingers F, to F, of the slotted rear section. This is the condition which exists just after the cartridge has been rammed into the chamber so that the weapon is loaded and ready to fire. In this state, a small gap G exists between the fingers and the surrounding bolt sleeve 19.

When the weapon is fired, casing 23A expands, as shown in FIG. 6, under the high gas pressure, causing fingers F, to F to deflect outwardly to close the gap. The ring segments on the fingers seize with great frictional resistance, the inner surface of bolt sleeve 19 to prevent its retraction until the pressure drops to a safe level. When the pressure drops to a point releasing the bolt, the bolt is pushed backward under the force of the reduced gas pressure to extract the empty casing.

Thus the pressures produced by the propellant gas serve to expand the cartridge casing, which cooperates with the chamber to retard the opening of the breech. The period of retardation is obviously dependent on the amount of pressure generated by the individual cartridges. Consequently, the weapon is, in a large measure, self-regulating, for it adjusts itself to variations in chamber pressure and pressure-vs-time curves encountered when using different lots of ammunition. For example, a given cartridge, when fired, will produce a maximum gas pressure which, say, is only moderately high, so that the breech-closing mechanism will be released sooner than when another cartridge produces a still higher pressure. Thus the retardation of the release of the breech block is correlated to the cartridge pressure-vs-time curves.

Although the chamber in accordance with the invention is shown as having segmented retarding rings of circular formation, it is to be understood that in practice these elements may have other configurations, for they may have square shapes or other formations to conform with different breech-block shapes and other weapon components.

SECOND EMBODIMENT Referring now to FIGS. 7 to 10, there is shown a second embodiment of a weapon incoporating a chamber in accordance with the invention. In this weapon, the barrel 15 is rigidly affixed by a barrel-retaining nut 26 to the bushing 27 of a receiver. Surrounding barrel 25 and concentric therewith, is a cylindrical bolt 28, the forward end of which abuts the rear end of receiver bushing 27. The bolt is relieved at its bottom to accommodate a cartridge magazine, and on one side or above, to provide a port for the ejection of spent cartridge casrngs.

Contained within bolt 28 is a firing pin 29 which is retracted by means of a firing-pin return spring 30. In operation, when a hammber 31 strikes the rear end of the firing pin, it is driven forward against the tension of its return spring 30 to strike and ignite the primer in the head 23C of the cartridge.

Although the mechanism described herein uses percussion ignition, it is to be understood that the invention is by no means limited thereto, for it is operable with electrical and other types of ignition systems.

The barrel 25 terminates in a chamber integral therewith, the chamber being generally designated by numeral 32. As shown separately in FIGS 8 and 11, chamber 32 is constituted by an unslotted collar-like forward section 32A which cooperates with the dilated casing of the cartridge to create a gas seal, and a rear section provided with longitudinally extending slots Sa, Sb, Sc and Sd, to define resilient collet fingers Fa, F b, Fe and Fd. The body of the rear section is relieved to define an annular, segmented lip L which serves as a retainer for a set of slot-sealing clips C,, C C and C the lip preventing the clips from sliding off the rear of the chamber.

Each of clips C to C, has an arcuate formation conforming to the curvature of the associated segmented sections of the chamber. Each clip is provided at its inner midpoint with a rib (R, to R.,) which is adapted to fit into and seal the corresponding slot of the collet section of the chamber.

When the clips are in place, they form a segmented sleeve about the segmented collet section of the chamber, the forward part of the sleeve being relieved to receive a split retaining ring 33 of spring material, as shown in FIG. 8. This ring serves to hold the clips to the chamber to prevent their loss when the barrel is removed from the weapon.

When, therefore, the cartridge is rammed into the chamber and is fired, as shown in FIG. 7, thereby ejecting projectile 238 which travels through barrel 23, the resultant dilation of easing 23A causes fingers Fa to Fd to deflect outwardly, and these in turn cause outward movement of the slotsealing clips C, to C, which then seize and bind the bearing surfaces on bolt 28 to prevent the bolt from moving backwards, until projectile 23B has left the barrel and pressure has dropped to a safe level.

The clips act to prevent the cartridge casing from excessive dilation that might otherwise cause it to burst as a result of an extremely high gas pressure. The clips, rather than the fingers of the collet section, bear the frictional load upon firing of the weapon, for it is the exterior surfaces of the clips which make contact with the breech block or bolt bearing surfaces.

FIGS. 9 and 10 illustrate the structural relationship of the clips and the bearing surfaces of the bolt. FIG. 9 shows the condition which prevails before firing, where it will be seen that casing 23A of the cartridge is snugly received within the collet-like fingers Fa to Fd of the chamber, the slots being sealed by the ribs R to R of clips C to C whose arcuate outer surfaces are spaced from the inner wall of bolt 28 to create a gap therebetween.

When the weapon is fired, the resultant dilation of casing 23A, as shown in FIG. 10, produces an outwar'dly directed pressure, closing the gap and forcing the clips against the bearing surfaces of the bolt to prevent retraction of the bolt until such time as the gas pressure drops to cause the casing to shrink to its original size.

While there have been shown and described preferred embodiments of a collet-chamber retarding system in accordance with the invention, it will be appreciated that many changes and modifications may be made therein without, however, departing from the essential spirit of the invention.

We claim:

1. A weapon adapted to fire a cartridge having a casing formed of a metal which dilates in response to the high gas pressure that is generated when the propellant in the casing is ignited, said weapon comprising:

A. a barrel extending from a receiver,

B. a chamber at the rear end of the barrel and disposed in a breech into which the cartridge is fed, said chamber including a cavity to accommodate the cartridge casing and a collar-like front section surrounding a complementary portion of the casing to form a gas seal therewith when the casing is dilated,

C. a bolt mechanism for ramming the cartridge into the cavity of said chamber and provided with a retractable sleeve which, in the firing state of the weapon, surrounds said chamber and blocks said breech, and

D. means to lock said sleeve to said chamber to maintain the breech blocked when said high pressure is generated, and to retard the retraction of said sleeve until the pressure has diminished to a safe level, said means including slots extending from the rear end of said chamber to said front section to define a collet-like rear section whose fingers are deflected by the dilated casing to effect a momentary locking action with the complementary portion of said sleeve.

2. A weapon as set forth in claim 1, further including limit means to permit said barrel to advance a short distance relative to said receiver when said cartridge is rammed into said chamber.

3. A weapon as set forth in claim 2, wherein said limit means is constituted by a barrel-retaining nut on the end of said receiver, a flange formed on the barrel, and a coil spring interposed between said flange and said nut and surrounding said barrel.

4. A weapon as set forth in claim 1, wherein said fingers are provided with external ridges adapted to frictionally engage the inner surface of said sleeve.

5. A weapon as set forth in claim 1, wherein said means to lock said sleeve includes a set of arcuate clips which surround said collet-like section, each clip having an inner rib entering one of said slots to seal same, said clips frictionally engaging the inner surface of the sleeve when the casing is dilated.

6. A weapon as set forth in claim 1, wherein said sleeve surrounds a bolt and is urged toward said chamber by a recoil spring.

7. A weapon as set forth in claim 6, wherein said bolt is provided with a head having a casing extractor thereon.

8. A weapon as set forth in claim 1, wherein said bolt mechanism includes a firing pin adapted to strike the primer head of said casing.

9. A weapon as set forth in claim 1, wherein said chamber is integral with said barrel. 

1. A weapon adapted to fire a cartridge having a casing formed of a metal which dilates in response to the high gas pressure that is generated when the propellant in the casing is ignited, said weapon comprising: A. a barrel extending from a receiver, B. a chamber at the rear end of the barrel and disposed in a breech into which the cartridge is fed, said chamber including a cavity to accommodate the cartridge casing and a collar-like front section surrounding a complementary portion of the casing to form a gas seal therewith when the casing is dilated, C. a bolt mechanism for ramming the cartridge into the cavity of said chamber and provided with a retractable sleeve which, in the firing state of the weapon, surrounds said chamber and blocks said breech, and D. means to lock said sleeve to said chamber to maintain the breech blocked when said high pressure is generated, and to retard the retraction of said sleeve until the pressure has diminished to a safe level, said means including slots extending from the rear end of said chamber to said front section to define a collet-like rear section whose fingers are deflected by the dilated casing to effect a momentary locking action with the complementary portion of said sleeve.
 2. A weapon as set forth in claim 1, further including limit means to permit said barrel to advance a short distance relative to said receiver when said cartridge is rammed into said chamber.
 3. A weapon as set forth in claim 2, wherein said limit means is constituted by a barrel-retaining nut on the end of said receiver, a flange formed on the barrel, and a coil spring interposed between said flange and said nut and surrounding said barrel.
 4. A weapon as set forth in claim 1, wherein said fingers are provided with external ridges adapted to frictionally engage the inner surface of said sleeve.
 5. A weapon as set forth in claim 1, wherein said means to lock said sleeve includes a set of arcuate clips which surround said collet-like section, each clip having an inner rib entering one of said slots to seal same, said clips frictionally engaging the inner surface of the sleeve when the casing is dilated.
 6. A weapon as set forth in claim 1, wherein said sleeve surrounds a bolt and is urged toward said chamber by a recoil spring.
 7. A weapon as set forth in claim 6, wherein said bolt is provided with a head having a casing extractor thereon.
 8. A weapon as set forth in claim 1, wherein said bolt mechanism includes a firing pin adapted to strike the primer head of said casing.
 9. A weapon as set forth in claim 1, wherein said chamber is integral with said barrel. 